There is a significant association between alcohol consumption and risk of MV infection. Virus is known to enter the brain early after infection, and neurological disease is a devastating sequela to IUV infection. Alcohol consumption may enhance IRV- I replication and neuroinvasion. Using the SIV macaque model of AIDS, our laboratory has shown that interactions mediated by adhesion molecules, chemokines and cytokines between peripheral blood mononuclear cells (PBMC) and microvascular brain endothelial cells (MBEC) are critical events in the neuropathogenesis of AIDS. There is no data for this during acute IRV infection. We have developed an in vitro model of the macaque blood-brain barrier (BBB) using autologous NIBEC and astrocytes to examine the specific events associated with neuroinvasion by SIV. Using this model, we propose to investigate interactions among PBMC, SIV, BBB and alcohol in vitro. This work is complemented by our experience with the macaque model of neuroAlDS and recent experiments by our collaborators showing significantly increased viral loads and proliferation of lymphocytes in acutely infected macaques receiving alcohol. We hypothesize that chronic alcohol exposure will enhance SIV neuroinvasion by facilitating trafficking of PBMC into CNS via effects on the B13B and/or on PBMC. To test these hypotheses we will use a combination of in vitro and in vivo approaches and propose the following Specific Aims: AIM I: Evaluate the effects of chronic alcohol exposure and SIV infection on the activation state and in vitro migratory properties of PBMC. AIM 2: Characterize the effects of alcohol exposure in SIV-infected macaques on the integrity of the BBB (in vitro and in vivo) and on the ability of PBMC to traverse the barrier. This will be achieved by: (a) examining the phenotype of the BBB in situ using immunohistochernical techniques to improve our in vitro model to facilitate studies of the effects of ethanol on SIV neuroinvasion; and (b) continued co-culture of autologous microvascular brain endothelial cells and astrocytes in the presence of alcohol. We will analyze interactions between cell types in vivo and in vitro and production of chemokines by glial elements relevant for development of SIV encephalitis. This proposal combines in vitro and in vivo models and expertise in the neuropathogenesis of AIDS of the SIV macaque model with expertise in the biological effects of alcohol abuse.